TRANSIENT PHASE-LOCKING OF 40 HZ ELECTRICAL OSCILLATIONS IN PREFRONTAL AND PARIETAL HUMAN CORTEX REFLECTS THE PROCESS OF CONSCIOUS SOMATIC PERCEPTION

Electrical potential oscillations in the range of 35-45 Hz (gamma wave s) have recently been shown to occur rather ubiquitously in the brain of awake humans. During selective somatic attention, we demonstrate a transient phase-locking of the gamma waves generated in the contralate ral prefrontal and parietal cortical areas that we had previously show n to be involved in such selective attention tasks. In line with other microphysiological evidence obtained on mammalian visual cortex, this selective functional synchronization between critical human brain are as (as far as about 9 cm apart) is proposed to reflect the transient ' binding' of discrete cognitive features that are processed in distribu ted neuronal assemblies of the brain whereby the conscious perception of an object or event can be achieved. On this basis we emphasize that the conscious function of the brain is neither epiphenomenal nor dela yed, but operates transiently to integrate relevant perceptual feature s at the time of target object identification and of conscious behavio ural decision.